1. Field of the Invention
Embodiments of the invention described herein pertain to the field of magnet wire. More particularly, but not by way of limitation, one or more embodiments of the invention enable a system and method for enhanced magnet wire insulation for electric submersible pump applications.
2. Description of the Related Art
Currently available magnet wire is not appropriate for some motor applications. Particularly, magnet wire used in motors for oil or gas pumping applications should be exceptionally reliable. When a motor is used in an oil or gas well, a wire failure or short is especially costly as the motor is deep in the ground. If the insulation of the magnet wire in the motor forms cracks, these cracks can cause premature failure of the motor.
In the case of an electric submersible pump (ESP), a failure of the motor can be catastrophic as it means having to remove the unit from the well for repairs. ESP assemblies in particular require that the magnet wire used be capable of surviving the high temperatures deep below ground. In addition, ESP pumps may sometimes leak, allowing some water to enter the motor. A magnet wire that is appropriately waterproof so as to prevent a short when exposed to such leakage would be an advantage in all types of pumping applications. Finally, magnet wires often are damaged when they are transported, incurring breaks, nicks or pinholes. This damage decreases the life expectancy of the wire. A magnet wire with increased durability during transportation would be an advantage in all types of magnet wire applications.
Currently available magnet wire is sometimes insulated with polyimide film, for example Kapton® (a trademark of E. I. Du Pont De Nemours and Company) tape. Polyimide film is a type of synthetic polymeric resin of a class resistant to high temperatures, wear, and corrosion, used primarily as a coating or film on a substrate substance. While for brevity this description uses Kapton® as an example of polyimide film, nothing herein limits the invention to the use of a particular polyimide film such as Kapton® tape. While Kapton® has the highest dielectric strength of any wire insulation currently available, it does have inherent weaknesses. Kapton® readily takes on water (is hydroscopic) and then degrades rapidly. The adhesive used to attach Kapton® tape to the wire may also delaminate at the extreme high temperatures of deep wells. Magnet wire wrapped with Kapton tape is also prone to damage during transportation.
Another currently available insulation for magnet wire is organic polymer thermoplastic insulation, such as PEEK (polyetheretherketone). While PEEK has sufficient dielectric strength at room temperature, it drops off rapidly when used above 500° F. Motor temperatures in high temperature wells may reach in excess of 550° F. Thus, PEEK is also not ideal wire insulation for use in ESP motors.
Therefore, there is a need for a system and method to produce enhanced magnet wire insulation that is more waterproof, durable during shipping and also reliable at the high temperatures for ESP applications.